Disruption of CISH promotes the antitumor activity of human T cells and decreases PD-1 expression levels

Harnessing the potential of gene-editing technology to overcome the current bottlenecks of CAR-T cell therapy in T-cell malignancies

T-cell malignancies (TCMs) include a diverse spectrum of hematologic cancers marked by complex biology and aggressive nature. Treating TCMs remains a critical unmet need in oncology with poor response to standard therapies. Chimeric antigen receptor (CAR)-T cell therapy is one of the most successful types of immunotherapy that has revolutionized cancer treatment, as evidenced by various approved products for CD19 B-cell malignancies and multiple myeloma. Nonetheless, due to some unique hurdles, such as the risk of CAR-T cell fratricide, product contamination with malignant cells, and severe T-cell aplasia, the translation of this treatment approach to TCMs has not been particularly successful. Moreover, irrespective of the type of treated cancer, CAR-T cell therapy can also present some complexities and potential side effects, such as cumbersome and costly manufacturing processes, impaired in vivo function, cytokine release syndrome (CRS), neurotoxicity, and leukemic transformation of CAR-T cells. Recent groundbreaking advances in gene-editing technology and the evolution of precise gene-editing tools such as the CRISPR/Cas9 system and its derivatives have opened a new way to overcoming the mentioned bottlenecks and paving the way for CAR-T cell therapy in TCMs. This review sheds light on how gene editing is being incorporated into CAR-T cell therapy to address current hurdles, enhance therapeutic efficacy, and improve the safety profile of CAR-T cell therapy in TCMs. Ongoing/conducted clinical trials are also discussed to provide a comprehensive view of the evolving landscape of genome-edited CAR-T cell therapy for TCMs.

CD70 CAR T cells secreting an anti-CD33/anti-CD3 dual-targeting antibody overcome antigen heterogeneity in AML

ABSTRACT

CD70 has emerged as a promising target in acute myeloid leukemia (AML), and we have previously demonstrated the potency of an optimized CD70-targeted ligand-based chimeric antigen receptor (CAR). However, here, we identify in vivo CD70 antigen escape as a limitation of single-antigen targeting. Combination targeting of CD70 and CD33 may overcome AML antigen heterogeneity. We hypothesized that modifying our CD70 CAR platform to secrete a bispecific T-cell engaging antibody molecule (TEAM) targeting CD33 (7033) would create a therapeutic window whereby AML heterogeneity could be addressed without increasing tissue toxicity. We found that CD33 TEAMs mediated specific cytotoxicity across AML cell lines, including CD33 or CD70 single-antigen knockout tumors. 7033 CAR T cells eradicated tumor in an in vivo mixed tumor model of CD70 antigen escape and outperformed the previously optimized CD70 CAR in a patient-derived xenograft. In vivo gene expression profiling of CAR T cells revealed enhanced 7033 CAR T-cell pathway scoring for persistence, activation, and T-cell receptor signaling. Additionally, CD33 TEAMs successfully redirected T cells isolated from patients with AML to activate, secrete cytokines, and kill tumor targets despite exposure to substantial prior cytotoxic therapies. In summary, our findings demonstrate the feasibility of our 7033 CAR to overcome AML heterogeneity and leverage the bystander T cells of patients; this approach warrants further study in patients with this dire clinical need.

Efficient multiplex non-viral engineering and expansion of polyclonal γδ CAR-T cells for immunotherapy

Gamma delta (γδ) T cells are defined by their unique ability to recognize a limited repertoire of non-peptide, non-MHC-associated antigens on transformed and pathogen-infected cells. In addition to their lack of alloreactivity, γδ T cells exhibit properties distinct from other lymphocyte subsets, prompting significant interest in their development as an off-the-shelf cellular immunotherapeutic. However, their low abundance in circulation, heterogeneity, limited methods for ex vivo expansion, and under-developed methodologies for genetic modification have hindered basic study and clinical application of γδ T cells. Here, we implement a feeder-free, scalable approach for ex vivo manufacture of polyclonal, non-virally modified, gene edited chimeric antigen receptor (CAR)-γδ T cells in support of therapeutic application. Engineered CAR-γδ T cells demonstrate high function in vitro and and in vivo. Longitudinal in vivo pharmacokinetic profiling of adoptively transferred polyclonal CAR-γδ T cells uncover subset-specific responses to IL-15 cytokine armoring and multiplex base editing. Our results present a robust platform for genetic modification of polyclonal CAR-γδ T cells and present unique opportunities to further define synergy and the contribution of discrete, engineered CAR-γδ T cell subsets to therapeutic efficacy in vivo.

Xianling Lianxia formula improves the efficacy of trastuzumab by enhancing NK cell-mediated ADCC in HER2-positive BC

Trastuzumab has improved survival rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC), but drug resistance leads to treatment failure. Natural killer (NK) cell-mediated antibody-dependent cell cytotoxicity (ADCC) represents an essential antitumor immune mechanism of trastuzumab. Traditional Chinese medicine (TCM) has been used for centuries to treat diseases because of its capacity to improve immune responses. Xianling Lianxia formula (XLLXF), based on the principle of "strengthening body and eliminating toxin", exhibits a synergistic effect in the trastuzumab treatment of patients with HER2-positive BC. Notably, this synergistic effect of XLLXF was executed by enhancing NK cells and ADCC, as demonstrated through in vitro co-culture of NK cells and BC cells and in vivo intervention experiments. Mechanistically, the augmented impact of XLLXF on NK cells is linked to a decrease in cytokine inducible Src homology 2 (SH2) containing protein (CISH) expression, which in turn activates the Janus kinase 1 (JAK1)/signal transducer and activator of transcription 5 (STAT5) pathway. Collectively, these findings suggested that XLLXF holds promise for enhancing NK cell function and sensitizing patients with HER2-positive BC to trastuzumab.

Cytoplasmic FBXO38 mediates PD-1 degradation

Comment on “FBXO38 is dispensable for PD-1 regulation” by Dibus et al,

Intracellular checkpoints for NK cell cancer immunotherapy

Natural killer (NK) cells are key innate immune lymphocytes, which play important roles against tumors. However, tumor-infiltrating NK cells are always hypofunctional/exhaustive. On the one hand, this state is contributed by context-dependent interactions between inhibitory NK cell checkpoint receptors and their ligands, which usually vary in different tumor types and stages during tumor development. On the other hand, the inhibitory functions of intracellular checkpoint molecules of NK cells are more similar across different tumor types, representing common mechanisms limiting the potential of NK cell therapy. In this review, representative NK cell intracellular checkpoint molecules in different aspects of NK cell biology were reviewed, and therapeutic potentials were discussed by targeting these molecules to promote antitumor NK cell therapy.

The ubiquitin-proteasome system in the tumor immune microenvironment: a key force in combination therapy

The ubiquitin-proteasome system (UPS) plays a crucial role in modulating the proliferation, activation, and normal functioning of immune cells through the regulation of protein degradation and function. By influencing the expression of immune checkpoint-associated proteins, the UPS modulates T cell-mediated anti-tumor immune responses and can potentially facilitate the immune escape of tumor cells. Additionally, the UPS contributes to the remodeling of the tumor immunosuppressive microenvironment (TIME) by regulating B cells, dendritic cells (DCs), macrophages, and Treg cells. Targeting the UPS in conjunction with immune checkpoint-associated proteins, and combining these with other therapeutic approaches, may significantly enhance the efficacy of combination therapies and pave the way for novel cancer treatment strategies. In this review, we first summarize the composition and alterations of the TIME, with a particular emphasis on the role of the UPS in TIME and its interactions with various immune cell types. Finally, we explore the potential of combining UPS-targeted therapies with immunotherapy to substantially improve the effectiveness of immunotherapy and enhance patient survival outcomes.

Ubiquitin modification in the regulation of tumor immunotherapy resistance mechanisms and potential therapeutic targets

Although immune checkpoint-based cancer immunotherapy has shown significant efficacy in various cancers, resistance still limits its therapeutic effects. Ubiquitination modification is a mechanism that adds different types of ubiquitin chains to proteins, mediating protein degradation or altering their function, thereby affecting cellular signal transduction. Increasing evidence suggests that ubiquitination modification plays a crucial role in regulating the mechanisms of resistance to cancer immunotherapy. Drugs targeting ubiquitination modification pathways have been shown to inhibit tumor progression or enhance the efficacy of cancer immunotherapy. This review elaborates on the mechanisms by which tumor cells, immune cells, and the tumor microenvironment mediate resistance to cancer immunotherapy and the details of how ubiquitination modification regulates these mechanisms, providing a foundation for enhancing the efficacy of cancer immunotherapy by intervening in ubiquitination modification.

Progress and pitfalls of gene editing technology in CAR-T cell therapy: a state-of-the-art review

CAR-T cell therapy has shown remarkable promise in treating B-cell malignancies, which has sparked optimism about its potential to treat other types of cancer as well. Nevertheless, the Expectations of CAR-T cell therapy in solid tumors and non-B cell hematologic malignancies have not been met. Furthermore, safety concerns regarding the use of viral vectors and the current personalized production process are other bottlenecks that limit its widespread use. In recent years the use of gene editing technology in CAR-T cell therapy has opened a new way to unleash the latent potentials of CAR-T cell therapy and lessen its associated challenges. Moreover, gene editing tools have paved the way to manufacturing CAR-T cells in a fully non-viral approach as well as providing a universal, off-the-shelf product. Despite all the advantages of gene editing strategies, the off-target activity of classical gene editing tools (ZFNs, TALENs, and CRISPR/Cas9) remains a major concern. Accordingly, several efforts have been made in recent years to reduce their off-target activity and genotoxicity, leading to the introduction of advanced gene editing tools with an improved safety profile. In this review, we begin by examining advanced gene editing tools, providing an overview of how these technologies are currently being applied in clinical trials of CAR-T cell therapies. Following this, we explore various gene editing strategies aimed at enhancing the safety and efficacy of CAR-T cell therapy.

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.

GMP-manufactured CRISPR/Cas9 technology as an advantageous tool to support cancer immunotherapy

BACKGROUND

CRISPR/Cas9 system to treat human-related diseases has achieved significant results and, even if its potential application in cancer research is improving, the application of this approach in clinical practice is still a nascent technology.

MAIN BODY

CRISPR/Cas9 technology is not yet used as a single therapy to treat tumors but it can be combined with traditional treatment strategies to provide personalized gene therapy for patients. The combination with chemotherapy, radiation and immunotherapy has been proven to be a powerful means of screening, identifying, validating and correcting tumor targets. Recently, CRISPR/Cas9 technology and CAR T-cell therapies have been integrated to open novel opportunities for the production of more efficient CAR T-cells for all patients. GMP-compatible equipment and reagents are already available for several clinical-grade systems at present, creating the basis and framework for the accelerated development of novel treatment methods.

CONCLUSION

Here we will provide a comprehensive collection of the actual GMP-grade CRISPR/Cas9-mediated approaches used to support cancer therapy highlighting how this technology is opening new opportunities for treating tumors.

Expanded Alternatives of CRISPR-Cas9 Applications in Immunotherapy of Colorectal Cancer

Immunotherapy for colorectal cancer (CRC) is limited to patients with advanced disease who have already undergone first-line chemotherapy and whose tumors exhibit microsatellite instability. Novel technical strategies are required to enhance therapeutic options and achieve a more robust immunological response. Therefore, exploring gene analysis and manipulation at the molecular level can further accelerate the development of advanced technologies to address these challenges. The emergence of advanced genome editing technology, particularly of clustered, regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) 9, holds promise in expanding the boundaries of cancer immunotherapy. In this manuscript, we provide a comprehensive review of the applications and perspectives of CRISPR technology in improving the design, generation, and efficiency of current immunotherapies, focusing on solid tumors such as colorectal cancer, where these approaches have not been as successful as in hematological conditions.

DIALing-up the preclinical characterization of gene-modified adoptive cellular immunotherapies

The preclinical characterization of gene modified adoptive cellular immunotherapy candidates for clinical development often requires the use of mouse models. Gene-modified lymphocytes (GML) incorporating chimeric antigen receptors (CAR) and T-cell receptors (TCR) into immune effector cells require in vivo characterization of biological activity, mechanism of action, and preclinical safety. Typically, this characterization involves the assessment of dose-dependent, on-target, on-tumor activity in severely immunocompromised mice. While suitable for the purpose of evaluating T cell-expressed transgene function in a living host, this approach falls short in translating cellular therapy efficacy, safety, and persistence from preclinical models to humans. To comprehensively characterize cell therapy products in mice, we have developed a framework called "DIAL". This framework aims to enable an end-to-end understanding of genetically engineered cellular immunotherapies in vivo, from infusion to tumor clearance and long-term immunosurveillance. The acronym DIAL stands for Distribution, Infiltration, Accumulation, and Longevity, compartmentalizing the systemic attributes of gene-modified cellular therapy and providing a platform for optimization with the ultimate goal of improving therapeutic efficacy. This review will discuss both existent and emerging examples of DIAL characterization in mouse models, as well as opportunities for future development and optimization.

CAR designs for solid tumors: overcoming hurdles and paving the way for effective immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has revolutionized immunotherapy by modifying patients' immune cells genetically. By expressing CARs, these modified cells can specifically identify and eliminate tumor cells. The success of CAR-T therapy in hematological malignancies, such as leukemia and lymphoma, has been remarkable. Numerous studies have reported improved patient outcomes and increased survival rates. However, the application of CAR-T therapy in treating solid tumors faces significant challenges. Solid tumors possess complex microenvironments containing stromal cells, extracellular matrix components, and blood vessels. These factors can impede the infiltration and persistence of CAR-T cells within the tumor. Additionally, the lack of target antigens exclusively expressed on tumor cells raises concerns about off-target effects and potential toxicity. This review aims to discuss advancements achieved by CAR-T therapy in solid tumors and the clinical outcomes in the realm of solid tumors.

Structure-based design of a phosphotyrosine-masked covalent ligand targeting the E3 ligase SOCS2

The Src homology 2 (SH2) domain recognizes phosphotyrosine (pY) post translational modifications in partner proteins to trigger downstream signaling. Drug discovery efforts targeting the SH2 domains have long been stymied by the poor drug-like properties of phosphate and its mimetics. Here, we use structure-based design to target the SH2 domain of the E3 ligase suppressor of cytokine signaling 2 (SOCS2). Starting from the highly ligand-efficient pY amino acid, a fragment growing approach reveals covalent modification of Cys111 in a co-crystal structure, which we leverage to rationally design a cysteine-directed electrophilic covalent inhibitor MN551. We report the prodrug MN714 containing a pivaloyloxymethyl (POM) protecting group and evidence its cell permeability and capping group unmasking using cellular target engagement and in-cell 19F NMR spectroscopy. Covalent engagement at Cys111 competitively blocks recruitment of cellular SOCS2 protein to its native substrate. The qualified inhibitors of SOCS2 could find attractive applications as chemical probes to understand the biology of SOCS2 and its CRL5 complex, and as E3 ligase handles in proteolysis targeting chimera (PROTACs) to induce targeted protein degradation.

CRISPR/Cas9: A Powerful Strategy to Improve CAR-T Cell Persistence

As an emerging treatment strategy for malignant tumors, chimeric antigen receptor T (CAR-T) cell therapy has been widely used in clinical practice, and its efficacy has been markedly improved in the past decade. However, the clinical effect of CAR-T therapy is not so satisfying, especially in solid tumors. Even in hematologic malignancies, a proportion of patients eventually relapse after receiving CAR-T cell infusions, owing to the poor expansion and persistence of CAR-T cells. Recently, CRISPR/Cas9 technology has provided an effective approach to promoting the proliferation and persistence of CAR-T cells in the body. This technology has been utilized in CAR-T cells to generate a memory phenotype, reduce exhaustion, and screen new targets to improve the anti-tumor potential. In this review, we aim to describe the major causes limiting the persistence of CAR-T cells in patients and discuss the application of CRISPR/Cas9 in promoting CAR-T cell persistence and its anti-tumor function. Finally, we investigate clinical trials for CRISPR/Cas9-engineered CAR-T cells for the treatment of cancer.